Drawing apparatus



May 25, 1948. F. L. DAvis, JR MZW DRAWING APPARATUS (PERSPECTOGRPH) Filed Sept. 2l, 1945 7 Sheets-Sheet l HvA/wr Z; DA ws uk.

' www A'WORNEY May 25, 1948. F. l.. DAVIS, .JR

y DAWING `APPARATUS (ERSPECTOGRAPH) Fileclv Sept. 2l, 1945 7 Sheets-Sheet 2 NORTH SOUTH mvENToR y f4/wr L. DAV/s Je.

ATTORNEY May 25, 1948. F. 1 DAVIS, JR 2,442,117

I DRAWING APPARATUS (PERSPECTOGRAPH) Filed Sept. 2l, 1945 '7 Sheets-Sheet 3 Fly. 3

INVENTOR. fk/wk 0,4 ws Je. BY

Arran/EY May 25, @4%. F. L. DAVIS, JR

DRAWING APPARATUS (PERSPECTOGRAPH) Filed Sept. 2l, 1945 '7 Sheets-Sheet 4 Ply,

0 PERS/E C 7'/ VE V/EW l lNvl-:NToR FRAN/f L. .0A ws ./A. BY

ATTORNEY May 25, 1948. F. L. DAvls, JR 2,442,117

v DRAWING APPARATUS (PERSPECTOGRAPH) Filed sept. 21, 1945 7 sheets-sheet 5 :'NvENToR HvA/wf L. 0A ws J/e. Y

BMM

ATTORNEY May 25, w@ F. L.. DAvls, .JR 2,442,117

DRAWING APPARATUS (PERSPEGTOGRAPH) Filed Sep.. 2l, 1945 '7 Sheets-'Sheet 6 ./'J 1-I3- 1 W?! I. @5 LAL-MALA 59 FZ 5 mi@ S 65] fg Jr INVENToR f y ,Y k'AN/f L. A ws JR.

ATroRNEY May 25, l948- F. L. DAvls, JR 2,442,117

DRAWING APPARATUS (PERS PECTOGRAPH) Filed sept. 21, 194:5I 'f sheets-sheet 7 v 45 y 4a s 47 4% BY Q ATTORNEY Patented May 25, 1948 DRAWING APPARATUS (PERSPEC- TOGRAPH) Frank L. Davis, Jr., Kenilworth, N. J.

Application September 21,17945, Serial No. 617,818

Claims.

The invention relates to drawing apparatus and more particularly to drawing apparatus for use by draitsmen and others in preparing perspective drawings.

Heretoiore, the preparation of perspective drawings has presented veXatious problems involving considerable time and being dependent upon the skill and ability of individuals for solution. Under such conditions, the accuracy and reliability of the resulting perspective drawings are dependent entirely upon the skill and ability of the individual draftsman and, obviously, vary in accuracy and reliability in complete accord with the degree of skill and ability possessed by the individual doing the work. It has been the practice for such individuals to use several wellknown so-called methods of graphical construction in preparing perspective views, which methods are time-consuming and involve many difliculties.

For a long time, attempts have been made to devise a machine that will perform all the routine operations of perspective drawing; So far, however, the manipulation of the machines has proved to be more time-consuming than the work they are designed to eliminate. One such machine recently designed cost about ve thousand dollars and a well-trained engineer was required to use it.

The instant invention has for its object to provide a novel apparatus for perspective drawing which is economical in cost ,and which avoids the objections and disadvantages inherent in existing machines.

The invention contemplates further the provision of a novel apparatus for perspective drawing which is simple in construction and which any intelligent person may operate efficiently without diiculty.

A further object of the invention is to provide a novel apparatus for perspective drawing which is accurate in its results and which may be used with a minimum of effort and which is of maximum reliability in the performance of its functions.

In addition, the invention seeks to provide a novel apparatus for perspective drawing which may be eiciently utilized to produce the desired results without the necessity for complicated mathematical calculations or measurements.`

Other objects will appear from the description hereinafter, and the features of novelty will be pointed out in the claims.

In the accompanying drawings,r which illus- 2 trate examples of the invention without dening its limits,

Fig. 1 is a diagrammatic view lillustrating a well-known method of graphical construction of a perspective View; g

Fig. 2 is a plan View of an elementary form of the novel drawing apparatus;

Figs. 3 and 3-0, constitute a plan View of ,any other form of the novel apparatus, Fig.' B-a being j the right-hand continuation of Fig. 3;

Fig. 4 shows a somewhat modied form ofthe Fig. '7 is a detail section on the line 1 7 off.;Y

Fig. 6:

Fig. 8 is a similar view on the line 8 8 of Fig. 6;l i

Fig. 9 shows a mounting included in the novel apparatus, with parts in section on the line .ll-'9 of Fig. 11 looking in the direction of the arrowv A at the opposite carriage;

Fig. 10 is a sectional view on line llil0 of Fig. 11 illustrating a rack andpinion arrangement embodied in the novel apparatus, and .Y

Fig. 11 is a fragmentary detail plan View of certain elements of Figs. 9 and 10.

Figure 1 illustrates a direct graphical method of constructing a perspective representationy of an object from scale drawings. 'Ihe plan View M o-f the object is actual and the elevation N thereof is a prepared view, obtained by projection from the plan view to obtain the relative position of the verticals, the heights being actual to scale.

The specific object, selected for purposes of e mum of construction lines to illustrate 'the method under discussion. It should be understood that neither this method nor the capacity of the novel apparatus to bev described hereinafter, are limited to the particular form or .dis-

position of the object selected for illustration.

In the plan view M the object is represented by the rectangle A, B, C, D. In the prepared orthogonal projected elevation N, the same letters A., I

B, C, D, identify the lower ends of all vertical edges, while the letters A', B', C', D indicate the upper ends of the corresponding verticals. Thus,

the extreme contour of the object in elevation, as illustrated, is defined by the rectangle A, A",C, C,

the dotted `line B, B shown inthe elevation 'N representing an invisible edgeon the Yfar side'Y of a carriage unit 4its component parts.

shown in Fig. 2. Small supporting rollers 21', 28 at `the ends of these other limbs are adapted to run on the drawing board. A (zo-ordinating ring 29 is located at the point at which said other limbs of the try squares 21 and 28 overlap each other and slidably embraces said other limbs of both try squares as illustrated. Ihe positions and movements of this co-ordinating ring 29, therefore, are always the resultant of the positions and'movements of the individual try squares 21 and 28 as will more fully appear hereinafter. An arm 3U is hinged at 3| to the coordinating ring 29, preferably on the Peripheral edge thereof, said arm 30 extending radially outward from said ring 29 a convenient distance and being provided at its outer free end with means for removably holding a pencil 32 or other conventional marking or indicating device. The arm 30 is pivoted or hinged on the ring 29 to enable the pencil 32 or its equivalent to be lifted out of contact with the associated drawing paper or sheet alt will when desired, as will appear more fully further on in the description.

In addition to the try square 21, a carriage 33 also travels on the track 25 and carries a pivoted sleeve 34 which slidably accommodates the beam 22, a similar pivoted sleeve 35 being carried by the try square 21 for the slidable accommodation of thebeamZI.

,Through the medium of a suitable tension member or transmission member, such as a cord, wire or chain 36 passing over pulleys 31 and connected at 38 with the carriage 33 and having its opposite ends attached at 39 and 40 to the try square 2B, the movements of Ithe carriage 33 in directions east or west causes the try square 28 to move in the direction south or north, respectively, a distance equal to the travel of the carriage 33.

The track 25 corresponds to the picture plane illustrated by the line PP in the graphical method illustrated in Fig. l. The tension member 36 and the pulleys 31 may be likened to the reference axis RL of Fig. 1, at which vertical projection lines are bent 90 degrees into horizontal projection lines having the same relative spacing.

To trace the operation of the machine I will make use of conventional plan and elevation views of a simple house form. The plan view 4I in such case will be attached to the drawing board (on which the apparatus is assumed to be mounted) in such a position relative to the pivot 23 eye E in Fig. 1) as is desired both as to distance from the eye and as to angular relation. A side elevation 42 and an end elevation 43 will be attached to said drawing board at such relative height to pivot 24 (eye E) as desired, and in a convenient location in the directions north or south, but with the ground lines of the two views 42 and 43 parallel to the straightedge I5'.

A blank sheet of paper 44 is attached to the aforesaid drawing board in the space normally within the range to be swept over by the pencil 32 or its equivalent, this sheet of paper 44 being de signed to have the desired perspective view produced upon it, directly, by the manual manipulation of the apparatus, through the interaction of This is accomplished without the necessity for vestablishing vanishing points, measuring points, visual rays or projection lines of any sort. The apparatus when in use operates as follows: n

With the pencil 32 held off the paper 44, the straight-edge I5' is moved lto coincide', as shown,

with the ground oor lines Ic, and h, y of the house, in the elevations 42 and 43, respectively, and the tracer point I1 is shifted into registry with the corner a in the plan view 4I. The pencil 32 is then placed in contact with the sheet of paper 44. The straight-edge I 5' is then held stationary and the tracer I1 is moved over the lines connecting the corners a, b, c, d and back to a, said lines representing the contour of the house in the plan View 4I. These operations cause the pencil 32 or its equivalent to draw the contour lines connecting the corners a', b', c', d and back to a on the sheet of paper 44. In a similar inanner with the straight-edge I5' shifted toward the west until its western line coincides with the lines pn and ml in views 42 and 43, respectively, and again held stationary in this shifted position,

lthe tracer I1 is again moved along the contour lines connecting a, b, c, d and back to a., whereby the pencil 32 or its equivalent will be made to draw the contour lines pn, nl', lm, and m'p on the sheet of paper 44 as also illustrated.`

By moving the straight-edge I5 westward through the distance of the point q from the line gh in the end elevation 43 and then, while holding said straight-edgein this position, moving the tracer point I1 along the line ef of the plan view 4I, the pencil 32 or its equivalent will be made to draw, on the paper 44, the line ef representing the ridge of the roof.

By holding the tracer I1 stationary over the point a in the plan view 4I and moving the straight-edge I5' through the distance gl in the end elevation 43, the pencil 32 or its equivalent will draw the vertical line ap'. In like manner, by holding the tracer I1 successively over the points b, c and d in the plan View 4I and moviner the straight-edge I5 through the same distance, i. e., gl in the end elevation 43, which distance vis equal to mit, m', or pk, the pencil 32 or its equivalent will produce the corresponding vertical lines n'b', Zc', and md, in correct location and of correct length on the sheet of paper 44.

For drawing the roof hip lines le, me, n f', and pf, a slightly different method of operation will be required since the hip lines of said roof are inclined, that is to say neither horizontal nor vertical. It may be noted at this point that the difliculty is not the inability of the apparatu-s to make the necessary movements but rather lies with the operator. This is due to the fact that to manipulate the apparatus correctly, it would be necessary for the operator to traverse the tracer I1 from.a to f in the plan view 4I (for example) at a rate of travel corresponding to the rate of travel of the straight-edge I5 from the points m or l to q in theend elevation 43. This obviously is a rather diflicult physical operation and would probably result in a wavy line for the line pf' on the sheet of paper 44.

The remedy lies in drawing the hip lines with the aid of a conventional straight-edge or ruler,

after the points e', f have been located either by having the apparatus draw the ridge line ef in the manner described above, or by using the pencil 32 (or preferably a pricker substituted for it) to just mark these points e', f'. In either case, after locating the'points c', f', the arm 3!) would be swung up out of the Way and the conventional straight-edge or ruler would be applied to draw the hip lines l'e, m'e, nf, and pf, and might also be used to draw the ridge line ef if not drawn previously.

It should be noted that the form'of apparatus illustrated in Figs. 2 and 3 does not require the pprepared-E.o,rtlnsgcnalA side-:\zieiz\1.. -l\--v in :F.ig. g1) fr b ut Y usesfeonventional elevationstdirectly. -This-,is...onev of.V thef chiefffpurposes.- in utilizingi the. Iparticular arrangement of` parts .illustrated infEig... 2. vActu.- al1y,.-Were the carriage. eiiprovdedmithya pencilor. equivalent,markingeimplement. it iWoul'd pro- Y duce-fsueh an. orthogonal. side. View, since theV Y straight-edges] if'uandd 5! alwaysintersect.y at a point/.correspondingtdthewertical andhcrizontal proection. linesJ thatY would` be i, drawn vte :obtain the-series .off points .-needed.. tosconstruct such a View.: The pivot 20:offsleeve.i9,for.instance,.may

be. 1 considered; as..producing imaginary View,

which. through. the `mediumof-` ,thebeam 22 movinglrtheecarriag'te .i Stands hence the try. square 2.8, translates-all eastfandfwestcutfofis .on. track 2.5

or picture plane, `into..movements .of the. .tryr` squarefZB of; equalsmagnitudaf in south-arid.A northf directions, respectively.

It .willibe evident.4 from; the fcregoing descrip-Y tion-.that by `simply shiftinghe. tracer point. if!V alongY the. lines of .the plan @i and .giving .the straightfedge l .different positions by. 'shifting saidestraightfedge along thetracksi. L21, theapparat-us showin-Fig. f2 Will-.locatejon the sheetd, a .,pointcorrespondngintheperspectivfe view to any f desired, point., ofV ythe Aobject represented in the views All, .142.fand 43; .Iurthermore,A this appar.

. Another formof my. apparatus, possessing certain; advantages cverthefone. rst describedanovej isslowninFigs. 3. and`3-a, With-.details illustrated more :fullylinl'igs -5., to.. 11, .Reference numerals .similar to.,.those used in Fig. 2Y have been. appliedto corresponding. elements of` Figs.. 3 to. Llinciusive; many elements of. .Figli are the same asfiiLEg. 3.

Parallel-'fixed tracks iii-a, and parallel-fixed Y t1-.ac1s.l2.-b, arranged atatothe tracks I..2-a,

serveas. guides. for pairs of. Wheels ifa, i3--b,

respectively, journalled onthe ends of straight-r edge's. l 5--a, i5-b, respectively. In addition, each of V.these straight-edges carries atv each end a pinion. i5..-.c, i5--d,.respectively, journalled about anV axis parallel to.` those of. the. respective' wheels (3f-41, lli-b, in.aposition.betweenthewlieels of thesame pair.. .Details ottheseparts are shown in Figs. 9, landfll. As. illustrated, each s tr'aiglfit-y edgecomprises Ytvi/,opapallel Ytubular ,members 5,

the ends of (which are l,clamped by meansof. screvvsil between. the split.. portions 41' ofAV heads M having lateral extensions 41.". Theseexte'nsionsV have. split. portions 61.-@ in which are fas- Y tened, by,thefclampingaction:of. screws .6.8, the

axles. 49 on which therespectivev-wheels. (I3-fc,

or. I3-b.). arejournalled. .The pinions (l5-c or IEA-d) aresecuredrigidlyto Athe ends of stub. 4shafts connected. rigidly by. a torque. member 5,.here shown as a tubetted axiallyiwithout Contact) into .oneofthetlibular `members 5.

The- .unit formedbytthe, torque member. 5 i .and the stub .shafts 56 is mounted to turn on ball |2-b, respectively; preferably these racks'are on.

Vthe undersdelof`- the top portions of carriers. iii-c (Fig. softhat the. racksand the'pinions l-x-ilfeslfl- .'40 particular problem, they..arcsccurcdto.slidestii ing therewith,areprqtectedrrom dustetc... 'Ib; i rack and. pinion ,device just described. i.. in .cpm .Y junction-with. .the vtorque .member .51.. iIlSllrQS ...aa

parallel Amotiono the straight-edge.1.5111911 iti-Tb, respectively.V

Along the straight-edge l5,.-a.. (which, extends..

over. thestraight-edge lt-.bgsee .3 and .4J`

are adapted to Y move. two `carriages L15-.1ste one.

of `which. is .pivotally .connecteia beam.,.2.2..-as.` 10, while. the. other. has.. al.,similar .piYQta1., .conr1e 2tion, With..a..beam 2l-1a. and.. isalsc.- provided .WithimeansY forremovably carryinga tracerpointf tifare, he. used in. .connection with. the.,plexil view. .s b aj .(Eis.. 3)v 'tacked tctliebperd.carrying my i drawing ..apparatili more .clearlyin.. Fig. Y 8) adapted tc... runlepetlig "thebcdypithc straight-.edgel- Y 'Each yof the beams. .2 I.a,.;.2.2;'-a, shown, es; made of parallel spaced tubes c Q1.1.11.cfi9'i3T at .their endsby suitableheadsthe pivots .llt-fa. ...ci at vtime. Vvends adjacent .to .the respective carriages i 6 1?. Near their other ends the beams.; .2 Les..

221s, Yextend in contact. with andrestilpcn'the. wheels., of inverted vcarriage units; 5,4': pircted Op,Y

pins 23-a,'2-a, respectively, which pins q,y 30, zi-r-aproiect between. thestubesfcrmins. De Qf' said beams.. These. pins are. stationery diiripg Veach particular problem. fciriifliichg ,the3 apparatus is .empmyed and cpnstitute itempcrarilr fixed.. .r slide andswmg. .These .pinsfiuncticnelsc es..

pivots.. for the carriages 5.41.', 'on the Wheelss 5.31. Y Y

pimts` an which' the .beams 21a-c, .22e-sm.

of. which. the said. beamsjmay move. lengthwise., Inprderthat" the position` `ofjiillese pivots. xrnay Y be changed according to the conditions .tifgteaclir whichv may be.Y adiustedelong. rods. or tubes' parallel to the .straight-.edge LE-,w and; t. ...e elements. 2-b, ,l-fb; the .slidcslA be. locked by set screwsor otherwi'sein psition.

reds Yor tubes .55. Thelattcr arel cp.ppected` at. their ends by sleeves A.55. normally' heldlstaticnary, as by means ,ci setscrewscnxedreach.

rodse which areperalleltc the. .straight-cdas.,

construction. cnablesthe .tubes 55.31.1.61. with their) the slides ,54, andV pivots 2S-figa, tobe adjiistedto p any desiredpcsitiop 'a10nethe1eschrcds 56,.-thc tubesllfe'maining parallel tc. the straight.-edge lE-a.V 1

15.--1)V extends .under the Ystiraielflt.-erige.. t5. al.

Atthecrossing. pcint arrange'. accable carriage. Y

lsf-b pigs sand. 4,) ccmpcsed cfitwcsimilar G0; unitsfmovable inuilisonleitherin Va direction.

lengthwise of the straight-edge l-a'fwhen the Y other straightfedgeY 1.5.-.lziricvesinthat .direction) .or in a direction. .length-Wise .Qt the? t Ystr.aight-esige lsb (when. thectlierstreigbtedee portion 51 provided' Alilith '-icrlscd, arms:-

which. aremeld ystills..axles. 58. by. tpeclamp s action-.oi VscreW-sf eolktheysplitl ends 51 arms. .'.Onthese-axles arefmoanied, urn

the interposition of b all; bearings..5.2-.=gz,thetiito wheels sas-a havingV beve1eaperippera1. edgesfgr Y 'ContactWithftheparallelmmbersgpi'streightf l5-f eiiseiifb, elseswliiclitheflower;sectigppicarf ,The tvvo piviotsv arev .perpendicular to 1the plane.. .Qisiich board,

Each carriage iti-a isprbvided with. wheels V55.7, having beveledvperipberies (like..the..0pessh.ewn.

wiseonthe spaced parallel tubes .wbichicrm to. .which they may havebeep. shifted aisne-.the

As. mentioned hereiplsefprejthe .straiehteedsel :57a moves. ip such.. direction) Details .ef 'gthcj Y Y iowersection orcarriase 16e-.b are. sliciiu'i.iifiliiss-V -5 'tio' `8,; inclusive. .This sectipn comprises@ bcdy 'nage Iii-t" is adapted to run. At its center the body portion 51 has a sleeve 51-a extending between the parallel members 45 of straight-edge lb. The upper section of carriage IG-b is a duplicate of the lower one, but is used in a position at 90 from the lower section, so that the wheels of the upper section will be in contact with the underside of the parallel members 45 of the straight-edge |5-a, and the two carriage sections are connected (preferably rigidly) by a pin 60 (Figs. 3, 4, 5 and 6). As indicated in Figs. 3 and 4, the upper section is inverted relatively to the lower section, so that while the wheels 53a of the lower section will run on the upper surface of the members 45 of straight-edge I 5-b, the wheels 53-a of the upper carriage section will travel on the lower surface of the members 45 of straight edge |5-a.'

The carriage IB-b and the right-hand carriage lli-a, are connected by a link 65 so as to move in unison along the straight-edge I5-a; the link 65 may, as shown in Figs. 5 and 8, be removably attached to outward extensions 58--a of the axles 58. Normally, that is to say, when the perspective to be produced is a so-called birds eye view, the carriage lli-b will be between the two carriages IG-a, as shown in full lines in Fig. 3. As above stated, the link 65, however, is detachable and may be transferred to the opposite side of the carriage lS-b, and the righthand carriage lli-a brought to a position between the other carriage lS-a and the carriage Iii-b, as indicated by dotted lines, for a purpose explained hereinafter.

A xed track 25-a, composed of two parallel rods or tubes connected at their ends (similar in this respect to the straight-edges l5-a, l5-b, and to the beams ZI-a, 22-a), extends parallel to the straight-edge l 5-a, and on this track are mounted to travel double carriages 21-d, 33a, similar in construction to the double carriage |6-b and provided with pins 21b, -33-b, extending between the parallel members of the beams 2I--a, 22-a, respectively, to form connections which, as these beams swing on their pivots 23-a and 24--a, respectively, will move the carriages 21d, 33-a, along their track 25-a. In this case, however, the upper and the lower sections of each of the double carriages 21-d, 33-a, will not always remain in the same relative angular position, and the connection 21-12, 33-b, of these upper and lower sections must therefore be a pivotal one, permitting the section which engages the beam ZI-a or 22-a to swing with the beam and thus to form different angles with the section which engages the track 25-a.

Each of the carriage sections engaging the track 25-a is provided with an arm 21-c, 33-c, respectively, to which is secured a cord, wire, or other tension member 36-a, 35-b, respectively, extending in opposite directions from said arm and passing in contact with guide pulleys .S1-a, 31-b, respectively, rotatable about xed axes. The left-hand position of these tension members and guides is shown in Figs. 3 and 4, while Fig. 3-a shows the right-handv continuation, both for Fig. 3 and for Fig. 4.

In Fig. 3-a, the tension member 36-a is shown attached to an arm 21 on a carriage 21 rigid with one end of a member 21-a having a similar carriage (without such arm as 21) at the other end, these carriages being mounted to travel along fixed parallel tracks 6| and also having pinions `|52 to travel along fixed parallel racks 63, these details being illustrated as agreeing in construction with the straight-edges I5-a, |5b, and their associated elements 41, l3-a, |3-b, IZ-a, |2-b, lll-a, I4-b, I5c, l5-d. 'lhe tracks 6l and racks 63 are parallel to the straight-edge I5-a. The tension member 35-b is attached to an arm 23 on a carriage 28 rigid with one end of a member 28-a having a similar carriage at its other end. These carriages travel on fixed parallel tracks 2li-a and also have pinions 62 arranged to roll on iixed racks 63 parallel to the tracks 26a. These parts associated with the tension member 36-b are of practically the same construction as those associated with the tension member 36-a, but their position is different, the tracks 2li-a and the racks 63 being parallel to the straight-edge lil-b; that is, at right angles to the tracks l6l and to the racks 63.

Along the member ZI-a is adapted to travel a double carriage 54 of substantially the same construction as the carriage I,6-b used at the crossing point of the straight-edges IS-a, l5-b. The lower section of this carriage has wheels running on the upper faces of the parallel rods or tubes forming the member 21-a, while the wheels of the upper inverted section run on the underside of the tubes forming the member 2li-a. To the carriage 64 is secured rigidly the co-ordinating member 25J-a, to which an arm BIJ-a is hinged or pivoted at 3l-a, said arm extending radially with respect to the central pin- B0 connecting `the two sections of the carriage 64, preferably at an angle of 45 relatively to the members 21-a, 2li-a. The outer end of the arm 30-a carries a marking device 32--a for producing, on a sheet 44-a fastened to the drawing board, a perspective View of the object represented by the plan view 4I-a and the elevation 42-a fastened to said board within the range of movement ofthe tracer point l1-a and of the straight-edge |5-b, respectively. A

The operation of the apparatus shown in Figs. 3 and 3-a is substantially similar to the one described in connection with Fig. 2. Thus, to draw a perspective representation of the top of the object (a cube has been chosen for the sake of simplicity), the straight-edge |5-b will be brought to a position in which the top line ofthe elevation 42-a (Fig. 3)*will register or coincide with a line [5-6 scribed or otherwise marked on the underside of a transparent strip |5--f rigidly connected with said straight-edge I5-b. The tracer point |1a will then be brought into registry with one of the corners .0f the plan view 4I-a, by properly moving the straight-edge I5-a along the tracks |2-a, and the carriage |6-a at the end of the beam 2 l-a, along said straightedge Iii-a. Every movement of this straightedge along the'tracks I2--a will impart a. like movement to the pivots 2lia and thereby cause the beams 2|-a, '22--a to swing about their stationary pivots or Iulcrums 23-a, 24-a,. the latter having been set to the desired positions. Such vmovement of the beams 2l-a, 22-a, will shift the carriages 21-d, 33-a, along their track 25-a in the same direction if the link 65 and thecarriage IG-a o f beam 22-a are in the position indicated by full lines in Fig. 3. With the parts in the position shown in this gure the tension members or transmission members 35-a, 36-b will cause the members 21-a, 28a, 32-a, to assume the position shown in Fig. 3`a. From the arrangement of the transmission members 36-a 36--b, illustrated, particularly near the upper assedio lefthand eornerof .Fieitfwill vloe clear that any .movement of the oarriaelelFI--dtowar 1 left will. cause the ..Inenoloer...2\' I-.Y.r.t4 to more y.to- .Ward the riehtand.itioeversawhile any.moverH ment of theearriaee ...33e-a; toit/ard. thelet. or

libe

toward the right will cause `the member@ .a to move up or down, respeotivelminrie. ,3f t is to say, toward .or- -away .from the riehteharid leads of the transmission member .35e-ain that view- I f startnewith the. .position .shown in .Eiss- .3 and. S-w, the traoernoint Il-a is vmovedalone .the outline of the yplan View 4.11ct and the straight-edge. 15eois held Stetionarmthe. re-

sulting movements .of .traoerfoarraee lli-a alone the straight-edge 15,-@ and of the .latter .alone .the tracks Vl2--o willswirie the beams 21a-a, v22.--11, .on their pivots 2.311, 2li-c, and cause theiri to shift the carriages-l217-fdL3S-q-Hd, respectively, along their xed track Z5-7a. This mOVQ- ment of the carriages 2l-yd, 3,3-7-a`, will be tranS- mitted by the vconnections 3B-Td, Sii-ZL to the .members Z'I-a, 28-a respectively, Kin Such a .Way

that the marking device sz-.4t 'will f produce at the ,upper .portion ofY theipeper 44a. .e .Perspective .representation of the top` of, the cube. If then 1the straightfedge l-bis shifted .in siichfashion LaS-to brinethe line |5fe into .registry With-.the

bottom line of the. elevationn 42e@ and V(While holding said straight-edge in this position), Ythe tracer point l'I-aA Yis, again moved alongl the outline of the plan view 4l-d, this will cause 3 Vtheniarlfzing device Y3 2i-a to produce, Iat the lower vportion of the paper lid-d, @perspective representation of the bottom or base of L the cu b e.

To .complete the'perspective view shovvninlig.

VS- d bring thetracer point ile-,dto one of the corners of theplan *View 4 I.-`a and, While hold? ingl said tracer point in this. position, move the straight-edge L5-band Withlit the carriagev l 6 -b,

' the link'i and the ,carriage 1S-a Yoo nriected to the 'loea'mf22-rzi, along the straight-edge 5f-a,

lfrom a. position Yin which the line l-.f-e, 4registers with the top' (or the bottom) .of the.' elevation @2f- Lt to. e Position .isfwhioh said@ lineresstefs with the'bottom or the top) .of said elevation.

one. of the. four vertical lines of the Vperspe.Active view 'd4-a; By repeating this operation'after shifting the tracer point [1f-atop. diierentcor.-

ner of the plan view vAlfa, I canse,the. marlii1-g deviceA I32- a "to vproduce anothe ofthe vertical lines of the perspective vew, j; lie latter being thus completed after four s uch operations. Since all'V the lines'oftheparticular object depicted (a cube) .are either`l'iorizontal or'wertica'l, the en.-

tire perspective 'view can be produced exclusively lo'y the inovenents imparted Yto the Vcoolldinating member 29-a and thepen'cil 32- a carried thereby.

' The perspective .View obtained Vas lust described is a view lookingfroni above, `or a birdsleyef View. `When it is desired to'r obtain aview'looking from below, orga Worms eye vieW, I s hift the parts in sucha way Athat ,the bearnsZ'lIf-c,

22 a instead of'loeing inclined inthe same direction (downwardly from left to right, iI1F ig. 3, fun lines) will be inclined in Qppesitefdirections so that'a lmovement of the straight-edge l5-a along 'the tracks IZ-a 7will cause simultaneous movements of the carriages '2 'lacZ/33465111 opposite directions .along the track 2 5-a. "forV .this purpose the link 65 andthe carriage 'I6-linfomi,- nected with vit areshifted' .tothe vopposite side .45 Yfijhisiwill cause. the loearrLZZY-: tosvving onits pivot Z4-Ya and, shiftJ theicarriage 3 3-ai.n ,s1lh `a way that the marking device 32-a Will. draw Yof -the-dotib1eqoarriaee Left.,k

straight, for cooperation. with certain ri eelt-b aad-orbite. ,1i Shifting tof.. one. of ,the .carriages .I 5.-o..;fro.1n. Side of the.; Carriage. 1er-l2. to the. `o.t.. l.er. .een effected reader- Y .Ie some .easesy .it .mayheoiedgrnore .con eaieet vp aratujs fFigBny l @.gfo 12h15 Ill-IT- Iiose. Instead ofnroridinsfoee @attiene I6d with @tracer pointv snel-ias'. ITL- gt .3, 1 furnish it ivitha'l, nter. H-eb/ indicating on Leela e ured to one. of. the

straietltredee, indicates on a .xedsGelel l 5ft-par: Y

View willlbe. obtained-.asin Eig.. ,3%. :I- t'vvx noted that Vforloring .the left-hand carnage ma off. Fig. 4, thedesiredl positionbtwo rat'etmovements 1are,es oliiilefi,one ley-shifting the ,otherby shifting the saidstraight-.edgegalpng -erationdesoribed in oonneetionwith Fig.- Ltfil .which the..oefriae.e havinefthe;tracernovit 1I-a .isshiited simultaneoiislitliri both-1 direotionsl With the anali.sement.Y of Fig. 4, .only vvertieal linessor horizontal lines parallel. to :the` picture ,plane ratus, other lines ,being drawn separatelygloy'a conventional ruler-or. straghedge after. determining their Uemi. points-wireline? aient-shear?- .paratlis a.

` I. desire it to be undestood.-t1.1at theater-31.1

straight-edge Yas Vapplied insreinbeioretogtne elfer'nents or .Inemhers .l5,. 15.', L5-T11, tgl), has been used only forti-1e `salie 'o'f..oonieefl.er1oean.d is 'not to be. interpreted li`te1e3i1-lv .Iniaotueder a strict,interpretation, only the riembel'lo Fiel 2` could tutori.eriy. be called .a streislet-e theleft-hand vertical lirie Qf-said memfpY points ofthe views. .42. ln Eiaioolopetation with View i2-.faiseffeoted,. n.ot..witn ani edge.. of themember 15+' WiththeliQel-:Q .AS

me in. Fia .3., ersdlit 13 straight lines for co-operation with plan views, elevations, or the like. A feature common to the members l5, l', lE-a, and l5-b, is that each of them has a straight longitudinal runway for a section of the double carriage I6' (Fig. 2) orA |6b (Figs. 3 and 4). Also, one member (l5 or I5-a) of each pair crosses the other member (I5' or |5-b) at right angles, and the longitudinal runway of said rst-mentioned member serves to guide another carriage (I6 in Fig. 2, lE--a in Fig. 3, and the left-hand member Iii-a in Fig. 4). This second carriage is pivotally connecte'd With one swinging ybeam (2l in Fig. 2, 2I-a in Figs. 3 and 4), while the otherswinging beam (22 in Fig. 2, 22-a in Figs. 3 and 4) has a similar connection with the mst-mentioned carriage. While in Figs. 3 and 4, the pivotal connection of the beam 22-a is not directly on the double carriage |6-b, it will be noted that the link 85 compels said double carriage to move lengthwise of the member l5-a in unison with the right-hand carriage IB-a to which the beam 22-a is connected pivotally. This right-hand carriage and the double carriage IG-b, therefore, travel as a unit along the member l5-a, and to this unit the beam 22--a is connected pivotally. It will further be noted that the horizontally-moving member (l5 in Fig. 2, |5-b in Figs. 3 and 4) of what may be called the transmitter portion of the apparatus will effect a vertical movement of one element 28 in Fig. 2, 28-a in Fig. 3-a) of what may be called the receiver portion of the apparatus, while the companion element (21 in Fig. 2, 2l-a in Fig. 3a) of such receiver will be given a horizontal movement in response to a vertical movement of the other movable member (I5 in Fig. 2, I5-a in Figs. 3 and 4) of the transmitter. It will also be noted that in Fig. 2, the co-ordinator 29 and with it marker-carrier 30 are actuated by the horizontally-moving vertical arm of the try square or carriage 21, and by the vertically-moving horizontal arm of the try square or carriage 28, each of said arms remaining parallel to its initial position throughout its movement.

The particular construction of carriage and its runway, the details of which are shown vbest in Fig. 8, is applicable in my apparatus wherever structural units of this character appear. That is to say, the element having a longitudinal runway comprises spaced parallel members of round cross-section, and the carriage traveling on said runway has wheels located between two neighboring parallel members and having beveled peripheries to engage such members. This construction of Wheels with beveled peripheries running on spaced parallel members is indicated in Figs. 3 and 4 at l2-a, |3-a; IZ-b, |3-b; I5-a, IB-a; 2I--a, 21--d, 54'; 22-a, :i3-a, 54'; and 25-a, 21-d, 33-a; also in Fig. S-a at 26-a, 28'; 21-a, 64; 2li-a, 64; and 6l, 21.

Although the present invention has been described in conjunction with a preferred embodiment, it is to be understood that modications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art will readily understand. Such variations and modications are considered to be within the purview and scope of the claims.

I claim:

1. In apparatus'of the class described, a structure consisting of two elements arranged one above the other at an angle to each other, and a carriage having two superposed connected sections co-operating with the respective elements,

each of said elements lcomprising spaced straight parallel members having rounded longitudinal surfaces, and each of said carriagev sections` having wheels with beveled peripheries fitted to engage said rounded surfaces of two neighboring parallel members of the respective element, the wheels of one carriage section engaging the upper surfaces of the lower element, and the wheels of the other carriage section engaging the lower surfaces of the upper-elefment- 2. An apparatus of the class described, comprising a planar base, a pair of elongated members mounted thereon in superposed relation for movement in planes parallel to the base, said members crossing each other at right angles, means on the base guiding and confining each member to a rectilinear path of movement in the direction of the longitudinal axis of the other, a carriage connecting said members at the point of intersection and movable-freely along the longitudinal axis ofeach, a second carriage on one of said members and movable freely along its longitudinal axis, two beams mounted to swing in a plane parallel to the base on pivot axes fixed during operation of the apparatus, said pivot axes being disposed on a line parallel to one of said elongated members, a pivotal connection between one beam and one carriage, a similar connection between the other beam and other carriage, a track on the base parallel to the elongated member having the two carriages thereon, an element movable along said track and having combined pivotal and sliding connection with one beam, a second element movable along said track and having similar connection with the other beam, marker means shiftable on the base, and an operating connection between each of said trackcarried elements and the marker means whereby to shift the marker means in accordance with movements of the elongated members and the beams.

3. An apparatus of the class described, comprising a planar base, a pair of elongated members mounted thereon in superposed relation for movement in planes parallel to the base, said members crossing each other at right angles, means on the base guiding and confining each member to a rectilinear path of movement in the direction of the longitudinal axis of the other, a double carriage at the point of intersection of said members, said double carriage having a portion engaging one member for movement along its longitudinal axis and having another portion engaging the other member for movement along its longitudinal axis, a pair of separate single carriages on one of said members and movable along its longitudinal axis, a connector between one of the single carriages and said double carriage, two beams mounted to swing in a plane parallel to the base on pivot axes xed during operation of the apparatus, said pivot axes being disposed on a line parallel to the elongated member mounting the single carriages, a pivotal connection between one beam and one of the single carriages, a similar connection between the other beam and the other single carriage, a track on the base parallel to said member on which the single carriages are mounted, an element movable along said track and having combined pivotal and sliding connection with one beam, a second element movable along said track and having similar connection with the other beam, marker means shiftable on the base, and a separate operating connection between each of the track-carried elements and the marker means whereby to shift the marker means iin: ac'commceiwith movementsibf itheelonv 'Ei Y ftifi-rst; apotione'engaging'fthe' other'merberffo @movements-along its E-longitudinall axis, gauf second @carriage engagingsone-"of's'aid members forjmove- 'Y :1-a'd'oiiblem'arriageconnectingsaidlamembers atfthe f- 5 ``'slipportnn saidbaserand movable'thereon tovari- Y 'oper'atfingwxr'itlrescrypointerfanether:cariageen- Y "-pen'dicular'to 'the longitudinal axis 'of thememhermouningbobhisaid carriages, ai p-airiof pivot ifalicomfifecti'on Wthoneofthe' pivot xtivlrres' and a Y #named carriage --a-`sealefixed to-" the member vr1'nfioiintiifig-said-lastineinecleariiage and eo'operting' `Witlfithe carriage pain-ter; twobeams mounted `@to"swing ffon'pyot -axes fixed;duringepeifationfof #and mauflieisrne:ms Loperative -in-"response"toY move-25 direction-:of the lorigitutlinakaxisofthesotherra"35 Y "connection withtl'i'ebtl'i'er carriage, and-'marker y.fxne'alnsresponsive' to themovements Qfsaidelonjgated'mefmber's and the beams.

" FRANKniDAVIs; Ja."

Y amemmziwsseinem) The vfollowing xrrefeieneesi.faireof reeordinthe le'i of :thisgpatent: Y f" UNITED "STATESiPATENTS 

